\section{Previous work}

Mueller and Whalley \cite{Mueller:1995:ACB:207110.207116} describe a
technique for avoiding conditional branches by path replication.
Their work includes heuristics for determining whether such
replication is worthwhile.  However, their technique for replicating
the paths is not based on graph rewriting, and they do not supply a
proof that their technique is correct.

To our knowledge, no existing research uses our technique based on
local graph rewriting, and we are unaware of any existing
\commonlisp{} compilers that implement it.
